Battery charger



FIG. 1 is a top, front and left side perspective view of a battery charger showing my new design;

FIG. 2 is a right side elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a bottom plan view thereof; and

FIG. 5 is a top plan view thereof. 

The ornamental design for a battery charger, as shown and described. 